package com.derive.education_service.utils;

import org.springframework.stereotype.Component;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 * 验证码生成
 * 使用：
 * 1、生成该类的一个实例
 * 2、调用该类的getImage（）方法获取一次性验证码图片
 * 3、通过该类的静态方法把图片写到指定的流中
 * 4、getText（）方法是获取验证码图片上的文本内容
 */
@Component
public class VerifyCode {
    private int w = 70;
    private int h = 35;
    private Random r = new Random();
    private String[] fontNames  = {"宋体", "华文楷体", "黑体", "华文新魏", "华文隶书", "微软雅黑", "楷体_GB2312"};
    private String codes  = "23456789abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
    private Color bgColor  = new Color(255, 255, 255);
    private String text ;
    //动态的生成字体颜色
    private Color randomColor () {
        int red = r.nextInt(150);
        int green = r.nextInt(150);
        int blue = r.nextInt(150);
        return new Color(red, green, blue);
    }
    //动态生成字体
    private Font randomFont () {
        int index = r.nextInt(fontNames.length);
        String fontName = fontNames[index];
        int style = r.nextInt(4);
        int size = r.nextInt(5) + 24;
        return new Font(fontName, style, size);
    }
    //画出验证码上的干扰线条
    private void drawLine (BufferedImage image) {
        int num  = 3;
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        for(int i = 0; i < num; i++) {
            int x1 = r.nextInt(w);
            int y1 = r.nextInt(h);
            int x2 = r.nextInt(w);
            int y2 = r.nextInt(h);
            g2.setStroke(new BasicStroke(1.5F));
            g2.setColor(Color.BLUE);
            g2.drawLine(x1, y1, x2, y2);
        }
    }
    //随机生成验证码图片上的验证字符（每次生成一个）
    private char randomChar () {
        int index = r.nextInt(codes.length());
        return codes.charAt(index);
    }
    //生成验证码图片
    private BufferedImage createImage () {
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        g2.setColor(this.bgColor);
        g2.fillRect(0, 0, w, h);
        return image;
    }
    //获得验证码图片
    public BufferedImage getImage () {
        BufferedImage image = createImage();
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        StringBuilder sb = new StringBuilder();
        // 向图片中画4个字符
        for(int i = 0; i < 4; i++)  {
            String s = randomChar() + "";
            sb.append(s);
            float x = i * 1.0F * w / 4;
            g2.setFont(randomFont());
            g2.setColor(randomColor());
            g2.drawString(s, x, h-5);
        }
        this.text = sb.toString();
        drawLine(image);
        return image;
    }
    //获得验证码图片上的字符
    public String getText () {
        return text;
    }

    public void output (BufferedImage image, OutputStream out)
            throws IOException {
        ImageIO.write(image, "JPEG", out);
    }
}